1. Field of the Invention
The present invention relates to compositions comprising fluorinated olefins, or fluorinated ketones, and at least one alcohol, halocarbon, fluoroalkyl ether, or hydrofluorocarbon and combinations thereof. These compositions are azeotropic or azeotrope-like and are useful in cleaning applications as a defluxing agent and for removing oils or residues from a surface.
2. Description of Related Art
Flux residues are always present on microelectronics components assembled using rosin flux. As modern electronic circuit boards evolve toward increased circuit and component densities, thorough board cleaning after soldering becomes a critical processing step. After soldering, the flux-residues are often removed with an organic solvent. De-fluxing solvents should be non-flammable, have low toxicity and have high solvency power, so that the flux and flux-residues can be removed now without damaging the substrate being cleaned. Further, other types of residue, such as oils and greases, must be effectively removed from these devices for optimal performance in use.
Alternative, non-ozone depleting solvents have become available since the elimination of nearly all previous CFCs and HCFCs as a result of the Montreal Protocol. While boiling point, flammability and solvent power characteristics can often be adjusted by preparing solvent mixtures, these mixtures are often unsatisfactory because they fractionate to an undesirable degree during use. Such solvent mixtures also fractionate during solvent distillation, which makes it virtually impossible to recover a solvent mixture of the original composition.
Azeotropic solvent mixtures may possess the properties needed for these de-fluxing, de-greasing applications and other cleaning agent needs. Azeotropic mixtures exhibit either a maximum or a minimum boiling point and do not fractionate on boiling. The inherent invariance of composition under boiling conditions insures that the ratios of the individual components of the mixture will not change during use and that solvency properties will remain constant as well.
The present invention provides azeotropic and azeotrope-like compositions useful in semiconductor chip and circuit board cleaning, defluxing, and degreasing processes. The present compositions are non-flammable, and as they do not fractionate, will not produce flammable compositions during use. Additionally, the used azeotropic solvent mixtures may be re-distilled and re-used without composition change.